ANTIMICROBIAL ACTIVITY OF EGYPTIAN MINOSA SEED EXTRACT AGAINST STAPHYLOCOCCUS AUREUS

ABSTRACT The escalating crisis of antimicrobial resistance, particularly in Staphylococcus aureus necessitates the urgent exploration of alternative therapeutic agents. Acacia nilotica (Egyptian mimosa) is a medicinal plant traditionally used in Northern Nigeria for treating infections, but scientific validation of its seed extract against local clinical isolates is limited. This study investigated the phytochemical constituents and in-vitro antibacterial activity of Acacia nilotica seed extract against a clinical isolate of Staphylococcus aureus from Maiduguri, Nigeria. Mature seeds were collected, authenticated, and extracted using 70% ethanol via maceration. Qualitative phytochemical screening and antibacterial activity using the agar well diffusion method at concentrations of 100, 200, 300, and 400 mg/ml were conducted. The antibiotic susceptibility of the isolate was also determined using the Kirby-Bauer disk diffusion method. Phytochemical analysis revealed the presence of proteins, alkaloids, phenolic compounds, saponins, steroids, quinones, and cardiac glycosides, but flavonoids were absent. The S. aureus isolate showed varying susceptibility to standard antibiotics, with the highest zones of inhibition for Erythromycin (30.00 mm), Ciprofloxacin (30.00 mm), and Levofloxacin (30.00 mm), and the lowest for Amoxicillin (18.00 mm). The seed extract exhibited dose-dependent antibacterial activity, with zones of inhibition of 10.00 mm, 17.00 mm, 25.00 mm, and 32.00 mm at 100, 200, 300, and 400 mg/ml, respectively. Remarkably, the activity at 400 mg/ml (32.00 mm) surpassed that of Amoxicillin (18.00 mm) and Cefuroxime (20.00 mm). These findings confirm that Acacia nilotica seed extract possesses significant antibacterial activity against Staphylococcus aureus validating its traditional use and highlighting its potential as a source of alternative antimicrobial agents to combat resistant infections.